ARM processors have 2 general instruction sets that they support: “ARM” and “Thumb”. Though there are different flavors of both, ARM instructions are 32 bits each and Thumb instructions are 16 bits. The main difference between the two is that ARM instructions have the possibility to do more in a single instruction than Thumb can. … Read more
use __android_log_print() instead. You have to include header <android/log.h> Sample Example. __android_log_print(ANDROID_LOG_DEBUG, “LOG_TAG”, “\n this is log messge \n”); You can also use format specifier like printf – __android_log_print(ANDROID_LOG_DEBUG, “LOG_TAG”, “Need to print : %d %s”,int_var, str_var); Make sure you also link against the logging library, in your Android.mk file: LOCAL_LDLIBS := -llog Ohh.. forgot … Read more
You just need to cast jintto int using C style casts. Same for jboolean to bool (if you’re using C99 bool type) or to uint8_t (if you’re using std int types) or to unsigned char. Open $NDK_ROOT/platforms/android-8/arch-arm/usr/include/jni.h and you’ll see jint, jboolean etc are just typedefs.
Here’s the most concise way I’ve seen: #include <android/log.h> #define LOG_TAG “someTag” #define LOGE(…) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__) #define LOGW(…) __android_log_print(ANDROID_LOG_WARN,LOG_TAG,__VA_ARGS__) #define LOGD(…) __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,__VA_ARGS__) #define LOGI(…) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__) … // Now you can log very simply like this: int foo = 42; LOGD( “This is a number from JNI: %d”, foo ); Also, make sure you link to the … Read more
If you can live with only supporting Android 4.1+, just set APP_PLATFORM := android-16 and you’ll be good to go. Behind the scenes it sets APP_PIE := true. Your binary will segfault on older SDKs. If you also need to support lower SDK levels, you’ll need to create two binaries. Some other answers I’ve seen … Read more
Android have no backtrace(), but unwind.h is here to serve. Symbolization is possible via dladdr(). The following code is my simple implementation of backtrace (with no demangling): #include <iostream> #include <iomanip> #include <unwind.h> #include <dlfcn.h> namespace { struct BacktraceState { void** current; void** end; }; static _Unwind_Reason_Code unwindCallback(struct _Unwind_Context* context, void* arg) { BacktraceState* state … Read more
I was able to prevent this annoying message; here is what worked for me. BACKGROUND: I am not using the NDK at all, and had never installed the NDK. However, as mentioned in another answer here by xsveda, this is a Gradle bug that is documented here: https://code.google.com/p/android/issues/detail?id=228424 and so even the “NDK-innocent” may become … Read more
I had the same problem on Debian Buster. Installing the Debian package libncurses5 solved it for me: $ sudo apt install libncurses5
It turned out that this approach does not entirely work when compiling a debuggable library. The release library is compiled with -O2 which optimizes out some infelicities, but the debug library is done with -O0 which reveals some additional problems. Furthermore, I wasn’t too happy about having to edit the boost files. So with some … Read more
Since Point is an inner class, the way to get it would be jclass cls = (*env)->FindClass(env, “com/example/ndktest/NDKTest$Point”); The $ convention for inner classes is not really clearly documented in the authoritative specs, but is entrenched in so much working code that it’s unlikely to change. Still, it would feel somewhat more robust if you … Read more